Rocket Stove Science

This year my son’s science fair project is a continuation of last year’s project on rocket stoves.  Last year he compared fuel magazines and combustion chambers for the right mix of air to fuel.  This year he built five different tin can rocket stoves to test which one would burn with lower emissions.   Here is a link to last year’s project:  https://hemetsunshine.wordpress.com/2012/04/08/inside-a-tin-can-rocket-stove.   For information on how to present an engineering design project, visit http://www.sciencebuddies.org/engineering-design-process/engineering-design-process-steps.shtml?from=Blog#theengineeringdesignprocess.

For the time spent preparing for science fair, we wanted a product we can enjoy long after science fair is over.    Last year’s rocket stove came in handy for camping and park picnics.   This year we built ten prototypes, but only included five in the project for testing.   My son found an improved rocket stove design that is as easy to build as last year’s model and burns virtually smokeless.  It did not burn with low enough smoke emissions for my husband’s liking, but we can use it for cooking on days when it is comfortable to have the windows open.

My husband is sensitive to smoke, but he doesn’t have a strong reaction to Duraflame logs.   Our goal is to continue to work on stove until it burns as clean a Duraflame.   One factor contributing to emissions is the type of wood burned.    We are burning Apricot, Persimmon and Pomegranate twigs.  Fruit trees, in general, render good firewood.  Apricot is prized for flavoring smoked meats.   Another factor is diameter size of wood burned.   The twigs are pencil to sidewalk chalk thickness.   We learned that once the fire is self-sustaining it is better to use the thicker twigs and stay with the same thickness for a a steady burn.   We didn’t have time to test the variety of insulation wewanted to try, but will do so after science fair.

The following are videos and notes we found either useful in explaining the rocket stove or science concept that helped my son think deeper about its design.  I will continue to add videos and articles that help explain the science of it.

ROCKET STOVE

ARTICLES AND COMMENTS ABOUT THE ROCKET STOVE

ROCKET STOVE BREAD OVEN

  • http://www.youtube.com/watch?v=z-g3jwv3R8Q – Aprovecho Rocket Bread Oven – Jan 23, 2012 – Dean Still, Executive Director of Aprovecho Research Center, demonstrates a prototype biomass bread oven using rocket stove principles. Rather than using earthen mass, this insulated stove using two steel drums heats quickly and efficiently using less wood. The oven uses the highly engineered combustion chamber from our institutional 60 liter stove, designed by Damon Ogle, that fully combusts harmful gasses and particulate matter.

HOW A ROCKET STOVE/MASS HEATER WORKS

HOW A SMOKE DETECTOR WORKS

CARBON DIOXIDE

CARBON MONOXIDE

FIRE

ARTICLES AND COMMENTS ABOUT FIRE

FLAME

BIOCHAR (TERRA PRETA)

HEAT TRANSFER

THERMOMETERS

ENERGY

INSULATORS AND CONDUCTORS

MATTER, MOLECULES AND ATOMS

MASS

DENSITY AND BUOYANCY

THERMODYNAMICS

INSPIRATION FROM GREATEST DISCOVERIES

* * *

VOCABULARY

  • Biomass stove – a stove that uses bio mass for fuel.  Wood is a form of biomass.
  • Combustion is a chemical reaction that produces heat and light. The most common form of combustion is fire. Most forms of combustion happen when the gas oxygen joins with another substance. For example, when wood burns, oxygen in the air joins with carbon in wood. Combustion can be slow or fast depending on the amount of oxygen available. Combustion that results in a flame is very fast and is called burning. Combustion can only occur between gases.
  • Uncombusted material is the material that was left unburned.
  • chemicals: A substance with a distinct molecular composition that is produced by or used in a chemical process.
  • Ash and smoke are the uncombusted materials left after a wood burning fire.
  • emissions: 1. The act or an instance of emitting.  2. A substance discharged into the air, especially by combustion.
  • char: wood that has been scorched, burned, or reduced to charcoal.
  • ember: tiny particles of wood that are so hot they glow.
  • amber: hard translucent fossilized resin produced by extinct coniferous trees
  • blaze: A brilliant burst of fire; a flame.
  • carbon monoxide is a toxic gas, but, being colorless, odorless, tasteless, and initially non-irritating, it is very difficult for people to detect.
  • creosote: The gummy, foul smelling, corrosive and extremely combustible substance that, if no precautions are taken, will coat the insides of everything it passes through. It is formed when volatile gases given off in the burning process combine and condense on their way out of the chimney.
  • soot: The fine black particles, chiefly composed of carbon, produced by incomplete combustion of coal, oil, wood, or other fuels.
  • flame: A hot glowing body of ignited gas that is generated by something on fire.
  • Configuration means arrangement of parts.
  • ignite: 1. a. To cause to burn. b. To set fire to. 2. To subject to great heat, especially to make luminous by heat.
  • conduction: the transfer of heat between substances that are in direct contact with each other.
  • convection: a process of heat transfer through a gas or liquid by bulk motion of hotter material into a cooler region
  • Radiation is when electromagnetic waves travel through space.  When electromagnetic waves come in contact with an object, the waves transfer the heat to that object. Electromagnetic waves travel through empty space. The sun warms the earth through the radiation of electromagnetic waves.

PROJECT NOTES

  • The rocket stove was invented by Dr. Larry Winiarski in 1982.
  • A properly built rocket stove will burn 75-90% less wood than an open fire.  This results in a 90% reduction in carbon monoxide and particles in the air.
  • A clean burning rocket stove is a rocket stove that has the most complete combustion.
  • Carbon monoxide is a product of incomplete combustion of organic matter due to insufficient oxygen supply to enable complete oxidation to carbon dioxide. The most common symptoms of carbon monoxide poisoning are headache, dizziness, weakness, nausea, vomiting, chest pain, and confusion. High levels can cause death. Poisoning can be difficult to diagnose because the symptoms mimic other illnesses
  • The rocket stove fuel is dried twigs.
  • Wood combustion causes solid wood to be transformed into heat, light, carbon dioxide, steam from water and wood ash.   Gasified water or water vapor in air is called atmospheric humidity.
  • Ashes are formed by components of wood that cannot burn so they remain solid.
  • The wood in this study are Apricot, Persimmon and Pomegranate twigs from my trees.   They were dehydrated to remove as much moisture as possible to reduce smoke emissions. The twig diameters used for this project were one fourth inch to one inch.
  • In chemistry, carbon dioxide is written as CO2, carbon monoxide is written as CO, and water is written as water H2O.
  • There are two different types of smoke detectors — ionization and photoelectric.  Our smoke detector is ionization type. It is triggered when particles in the air reach 0.1 micron. One micron is 1/25000 of an inch; a 0.1 micron particle is 1/250000 of an inch.
  • Limiting heat loss helps the oven burn more efficiently. Heat loss can happen by conduction, convection, radiation and infiltration.  Insulating the combustion chamber is a way to prevent some heat loss.
  • biochar
  • The difference between coal and charcoal is: Coal is solidified decayed plant matter, compressed over a long time. Charcoal is hardwood that has been heated to a high temperature in the absence of oxygen.  You can cook food with charcoal, but exposure to a coal fire would poison your food.
  • Buckminster Fuller, said: Fire is the Sun’s energy unwinding from the tree’s log. Each ring of the tree is the impoundment of one year of the Sun’s fire (energy).  So the fire is many years of the Sun’s flame, now unwinding from the tree.
  • In Greek mythology, Prometheus was a Greek deity that was said to have brought fire to humans.
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About Hemet Sunshine

I am a homeschooling mom living in Hemet, California. I am interested in building a better community for the ones I love.
This entry was posted in Chemistry, Engineering, Hemet SUNshine, same name different blog, Physics. Bookmark the permalink.

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